[A123] Kant writes that "the imagination is a faculty of a priori synthesis". The transcendental function of the imagination "aims at nothing but necessary unity in the synthesis of what is manifold in appearance". Without this action, there could be no "unitary experience" and thus "experience itself...[is] possible only by means of this transcendental function of the imagination". [B152] Kant asserts that the synthesis of the imagination conforms to the categories, that the imagination is "a faculty which determines the sensibility a priori", and that this transcendental imagination "is spontaneity" and is "an action of the understanding on the sensibility". He also calls the transcendental imagination the productive imagination, which he distinguishes from the reproductive imagination ("whose synthesis is entirely subject to empirical laws"), which falls within the domain "not of transcendental philosophy but of psychology".

Traditionally, the mental capacity for experiencing, constructing, or manipulating 'mental imagery' (quasi-perceptual experience). Imagination is also regarded as responsible for fantasy, inventiveness, idiosyncrasy, and creative, original, and insightful thought in general, and, sometimes, for a much wider range of mental activities dealing with the non-actual, such as supposing, pretending, 'seeing as', thinking of possibilities, and even being mistaken. See representation .&ltDiscussion &gt &ltReferences &gt Nigel J.T. Thomas